Position of cells

Hello.
We have a "tree" with a start point at the left and the "arms" going to the right. The problem is, that all cells have different width and the cells of different arms don't stay "one under the other".
Is there any possibility to fix the witdth of a cell? Or: Is there a possibility to position the cells in "columns"? We need that as we want to categorize the "columns" for a function analysis. At the moment, all our cells have a white line of "-----" in the first line to have alll cells same width. But that is not a good solution.
Thanks, Felix